Apparatus for producing matrices in galvanic baths



"Aug.22, 1944. A. WQITSCHECK 2,355,639

APPARATUS FOR PRODUCING MATRICES IN GALVANIC BATHS Filed May 26, 1941 2Sheets-Sheet 2 I 16 1 jfz'gr. 1s

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Patented Aug. 22, 1944 1 APPARATUS FOR PRODUCING'MATRICES" 7 N GALVANICBATHS Arno Woitscheck, l?orz, near-Cologne, Germany; vested in the AlienProperty Custodian I 5 Application May 26,1941, Serial No. 395,318 7 rIn Germany May l7, 1940 Claims. (0-1. ant-2 86) The object of theinvention is to provide, in place of the known method of producingmechanically recorded sound-bands in a galvanic bath, a method of and adevice for the production perfect sound band matrices in the most simple manner and within the shortest possible time. It relates especiallyto the production of matrices from long and comparatively wide soundbands, in whose sound record layer are cut a. number of sound groovesrunning parallel or nearly parallel to'the edge of the band, though theinvention may likewise be applied to short and narrow sound bands.

"The original sound bands, afterhaving been recorded in known manner,are provided with an electrically conductive coating, for example agraphite coating, and are then placed in a galvanic-bath, in which agalvanic deposit-of the desired thickness of the sound bandmatrix isproduced on the surface of the band that has been renderedconductive. Inthis operation, not only the handling of the original sound band, whichis provided with an extremely delicate layer, for example a wax layer,but particularly the electric connection of the conductive surface ofthe band, cause considerable difliculties. Since the conductive coating.on the recorded side of the: band has to be extremely thin, becauseotherwisethe reproduction of the sound record by the matrix would beimperfect, care must be taken that the coating produced in the galvanicbath grows as quickly and uniformly as possible, and at the same timethat the band-shaped matrix has in all parts the same thickness,

In order to achieve these objects, the invention provides a currentconnection at the conductive recorded surface of the original sound bandfor the entire length of this band, ensuring an uninterrupted contactalong the edge of the conductive surface strip, preferably along bothedges of this strip. For this purpose, the original sound band isclamped at its longitudinal edges on to a current carrying rail by meansof conducting angular strips, the one leg of which rests on said rail,whereas the other leg lies on the edge of the conductive surface of thesound band. The free surfaces of said rail and of the conducting strip,serving to clamp fast the sound band, are provided with an insulatinglayer or cover, and then the band is brought into the galvanic bath.

In order to save room and to be able to more easily handle the soundband, it is known to wind the sound band in a helical line upon a drumwhen it is immersed in the galvanic bath. As a carrier for the soundband, the invention proiii vides, instead of the drum, a helicalcurrent-com ducting rail with clamping devices for the soundban'darranged along the edges of the rail. This helical rail isadvantageously mounted to rotate and is connected by means of a slipcurrent conductor.

According to the invention, the clamping devices for the sound bandcomprise segmental sections of angularly bent metal strips which, on theone hand, bear by means of angular segments of insulating materialagainst the current conducting rail and, on the other hand, against theconductive surface of the sound band.

A constructional example of the device for car-' rying out themethod-according to the invention devices for the original sound band,on an en-' larged scale and a I a Fig. 5 is a top view of the currentconducting mil with the clamping devices attached thereto,

also on an enlarged scale.

The current conducting rail 1, consisting for example of copper, has, aswill be seen from the drawing, a helical shape and forms at-its outercircumference a smooth resting surface 2 for the original sound band ofwhich a matrix is to be made. The current conducting rail is carried bya cage consisting of an upper ring 3, preferably of copper, a lower ring4, and rods 5 running between these two rings. The rods 5 pass throughthe convolutions of the current conducting rail and serve to carry thisrail and to ensure a uniform spacing of the individual convolutions ofthe rail; they are conductively connected to the rail l and the rings 3and 4.

The ring 3 is connected by means of spokes 6, preferably consisting ofcopper, with a hub 1 of insulating material rigidly attached to avertical shaft -8 rotatable about its axis. a slip ring 9 being providedat the circumference of the hub and being conductively connected to thespokes 6. The current conduction to the slip ring 9 is effected by thediagrammatically indicated brush it.

The ring 4 has spokes II supported by a hub 12 of insulating material,which is carried by the shaft 8 at its lower end.

To the rail I are attached, at the side at certain distances, bolts l3of insulating material serving to attach the clamping devices for thering to the sound band of which a matrix is to be made. The bolts I3carry nuts I4, also consisting of insulating material. The clampingdevices for the sound band consist of segmental sections of angularlybent copper strips l5 and of angular segments I6 of insulating material.The copper strips I5 have longitudinal slots I1, and the segments I6have longitudinal slots I8 in which, in the operating position of theseclamping means, the bolts I3 are disposed.

The sound band, of which a matrix is to be made, for example, consistsof a carrier layer I9 and a sound record layer 20 of wax, into which thesound grooves 2| are cut. After the recorded surface has been madeconducting, for example by coating it with graphite or in some otherway,the band is found upon the outer surface 2 of the'helical rail I so thatthe carrier layer rests on the rail. As this winding proceeds, first thecopper strips I5 and then the insulating segments I6 are slipped withtheir slots I1 and I8 on to: e bolts I3 of the rail I, whereupon thenuts I are tightened. In this way, the leg I5a of the copper strip I5 ispressed against the lateral face of the rail I, whereas the leg I5bprojects over the edge of the original sound band and bears against theconductive surface of this band. As wil1 be seen from the drawing, onecopper strip I5 follows the other copper strip I5 so that the currentconnection at the conductive recorded surface of the original sound bandis ensured over the entire length of this band by uninterrupted contactsalong the edge of the conductive surface strip, at both edges of thisstrip. Consequently, when the sound band is brought into the galvanicbath, the material forming the matrix, for example copper, very rapidlyaccumulates on the surface of the band of which the matrix is to bemade.

When the sound band is completely attached to the current conductingrail, the remaining free surfaces of the rail and of the conductingstrip serving to clamp the sound band on to the rail are provided withan insulating layer or cover. This may be done, for example, by applyingan insulating varnish. The same refers to all other condifcting surfacesof th ring 4, the rods 5, the spokes II, and the shaft 8. Of course, allthese parts may just as well be varnished before winding the sound bandupon the rail.

The device described above, carrying the sound band, is immersed in thegalvanic'bath 22, into which the anodes 23 dip, in a manner known perse, said anodes being suspended on a conductive ring 24 connected at 25to the source of current. While the matrix is being formed, the rail Iis rotated by the shaft 8 with respect to the anodes 23.

When the matrix has been formed, the rail I is drawn out of the bath,the clamping devices I5, I6 are removed, and the matrix band formed isdetached from the original sound band while the latter is still wound onthe rail.

What is claimed, is:

1. An apparatus for producing matrices in a galvanic bath frommechanically recorded flexible sound bands having a prepared conductivesurface at the recorded portion thereof, comprising a supporting cathodefor receiving the band with its recorded and prepared surface exposed,said cathode having a helical rail comprised of spaced convolutions ofchannel-shaped cross-section, angular conductive segments extendingaround the edges of said helical rail and adapted to overlie the marginsof the band in coextensive conductive relation with said conductivesurface thereof, angular insulating segments extending over the outersurfaces of said conductive segments, and clamping means for securingthe segments in position.

2. An apparatus for producing matrices in a galvanic bath frommechanically recorded flexible sound bands having a prepared conductivesurface at the recorded portion thereof, comprising a supporting cathodefor receiving the band with its recorded and prepared surface exposed,said cathode having a helical rail comprised of spaced convolutions ofchannel-shaped cross-section, angular conductive segments extendingaround the edges of said helical rail and adapted to overlie the marginsof the band in coextensive conductive relation with said conductivesurface thereof, angular insulating segments extending over the outersurfaces of said conductive segments, and clamping bolts extendingthrough the channel members for securing the segments in position, thesegments having slots for receiving the stems of the bolts and with openends directed toward the axis of the helix for facilitating the placingand removal of the segments on the bolts.

ARNO WOITSCHECK.

CERTIFICATE OF CORRECTION. Patent No. 2,556,659. August 22, 19th.

ARNO woITsCEECK.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 2,first column, line 17, for the word "found" read -wound-; and that thesaid Letters Patent should be read with this correction therein that thesame may conform to the record of the case in the Patent Office.

Signed and sealed this 28th day of November, A. D. 191411..

Leslie Frazer (Seal) Acting Commissioner of Patents.

